Added dedicated entrypoint

Dockerfile

@@ -33,4 +33,5 @@ RUN yarn install --check-files; bundle exec rake assets:precompile
 
 EXPOSE 3000
 
-CMD cd /app && rake 'db:migrate' && bundle exec rails server -b 0.0.0.0
+ENTRYPOINT ["/bin/bash"]
+CMD ["/app/entrypoint.sh"]

entrypoint.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+DATABASE=${DATABASE:-db/database/snibox.sqlite3}
+
+if [ -f /app/tmp/pids/server.pid ]
+then
+    rm -f /app/tmp/pids/server.pid
+fi
+
+cd /app
+
+if [ ! -f $DATABASE ]
+then
+    rake 'db:migrate'
+fi
+
+bundle exec rails server -b 0.0.0.0